Sound reproducer



2 Sheets-Sheet Aug. 14, 1928.

` G. STROBINO SOUND REPRGDUCER Filed oct. 29, 1926 Aug. 14, 1928.

G. STROBINO SOUND REPRODUCER Filed Oct. 29, 1926 2 Sheets-Sheet 2WITNESS rofry Patented Aug, 1.4, 1928.

UNITED STATES.

GASTON STROBINO, OF PATERSON, NEW JERSEY.

SOUND REPRODUCER.

Application led October 29, 1926. Serial No. 144,986.

In my application for patent for a sound Teproducer, Serial No. 74,276,tiled Dec. 9, 1925, I have disclosed a sound reproducer of the type inwhich van elastic vibratory. structure including a resonator isintermittently tensioned and thereby vibrated by electromagnetic meansthereon, such sound reproducer distinguishing from others in its classby said structure being normally tensioned and as thus tensioned holdingthe elements (electro-magnet and armature) of said means in operativerelation to each other and by the presence of .elastic means holdingsaid structure thus normally tensioned. The 0bjeet of the invention isto provide a reprodncer which shall reproduce in more faithful imitationof the originals than ordina-ry reproducers or receivers soundsdiifering from each other through a wide range of frequency. In thisapplication I 'claim one of the species of the invention set forth insaid application Serial No. 74,276.

In the drawings` Fi g. 1 is a side elevation of a resonator-includingvibratory structure embodying the invention;

Fig. 2 is a view of said structure as seen when viewed from the right inFig. 1;

Fig. 3 is a plan of vsaid structure with the resonator removed; and

Figs. 4 and 5 are views illustrating two modifications and in which theresonator appears in each case in section and the remainder of thestructure in side elevation.

The vibratory structure including a resonator in the example illustratedin Figs. 1 and 2 is represented bv the U-shaped elastic metal member 1,which may be a permanent magnet, and the resonator 2. preferably ofwood, member L being suitably secured at 3 to the resonator so that itstands in a plane perpendicular thereto and so that one arm, 1. istherefore free to vibrate independently of the resonator: the arm 1awill of course be the freer to vibrate if as little as possible of theother arm, 1", is damped, wherefore I form the latter arm with a.projecting base,

as shown, affording limited contact with the resonator.

Said structure is normally tensioned by elastic means, as thus tensionedholding the elements of the electro-magnetic means for intermittentlytensioning it in operative relation toeach other. In the present casethis tensioning means is as follows: 4 is an elongated stiff elasticflexible piece here in the form of a leyer which is fulcrumed andthereby has a bearing on theset-screws 5 in a projection of the arm 1aof member 1 so as to oseillate in the plane of member 1 and has itsshorter arm 4a bent toward arm l",v of member 1 and its longer arm bentofi' in the same direction and preferably engaged in a' notch 1X of saidmember. An adjusting screw 6, tapped into arm lb of member l.'

bears against the adjacent side of lever 4 at about the middle of itslonger arm, and between this screw and the bent or closed end of member1 another adjusting screw 7 is tapped into arm la of said member andbears against the longer arm of said lever. The electro-magnetic meansoractuator here includes two electro-magnets, either of which may betreated as the armature of the other,

.nected at 8a. The power and eiiiciency of the device being described,which is designed for use especially in connection with radio apparatuswhere the operating current is weak, depend veryv largely on the tensiondeveloped in member 1, the fact that said tension is maintained byelastic means, and also on the possibility of nicely calibrating the gapor spaeingbetween the elements of the electro-magnetic actuator. Ineffecting adjustment for these purposes the screw 7 may first be turnedto press the longer arm of elastic lever 4 downward, which elevates itsshorter arm and opens the gap, and then screw 6 turned to bow said armbetween screw 7 and fulcrnm 5, which depresses its shorter arm andcloses the gap. The present construct-ion is such `that adjustment canbe i effected so that for any given gap required between said elementsthe tension may be varied, or for any given tension the gap may bevaried, and always the tensioned structure is Vheld tensioned byelast-ic means. vWhile it isof course an advantage that an instrument beaorded which, as herein shown, is self-contained, still this is notindispensable, for the invention also contemplates a rsystem to' bevibrated including the elastic iexible vibratory structure and means (as4 and 6 7) to exert variable elastic flexing pressure thereon at eitherof two points thereof in substantially a common plane of fiexure, incombination with electro-magnet and armature elements arranged one onthe part of said system which is moved on flexing said structure and theother on another part of said system. And in this broad statement it isto be observed that it is not material that said means to exert pressureon said structure have its elasticity afforded by a fulcrumed orlever-like part (4), though such a construction lends itself to amovement-together as against a movementapart in forming the gap and alsoa veryv nice Calibrating of the gap, which is necessary when themechanism is used in radioreception, where very weak currents must bedepended upon to energize the electromagnet.

In Figs. 4 and 5 I show two different applications of my invention tosound reproducers of the so-called loud-speaker type for use inconnection with radio-receiving apparatus: Fig. 4: Two concavo-convexparts 10, as of suitable wood, bear against each other at theirperipheries, being there held together by the screw-bolts 11, which maybe arranged at suitable intervals. The upper one has sound outlet means12 andthe lower one supporting legs 13, which may if desired be composedof the same material as such resonator and thus form resonatingextensions thereof. The member 1 is contained within the casing formedby these two resonators, being secured to the lower one. A screwl 14 issecured to and extends up from the otherwise free arm 1 of said memberthrough a suitable aperture in the upper resonator and on its upperthreaded end is a knurled nut 15. Fig. 5: The parts 16 are formed thesame as parts 10, and the member 1 is contained and secured in thecasing they form the same as in Fig. 4; but here a turn-buckleadjustment 17 (comprising a nut screwed onto the adjoining ends ofrcversely threaded screws one lof which is fixed in arm 1 of member 1and the other of which bears against the upper resonator) is interposedbetween arm 1 and the central oint of the upper resonator 16, tending toiiold it tilted as shown (one or two of the screw-bolts 18 whichpenetrate the peripheries of the two resonators being drawn 'up more orless tight and the others left loose or serving mainly as guides and tolimit the upward or opening movement of the upper resonator), and thereis means to draw the upper resonator downward consisting of a screw 19in the lower resonator penetrating the upper one and having a thumb-nut20 bearing on the latter.

In both cases the. instrument contained in the casing formed by the tworesonators may be pre-adjusted (as by the manufacturer) to such anextent that the user has only in Fig. 4 to turn nut 15 in the directionto pull the arms 1n and l" apart, or in Fig. 5 to turn nut 20 in thedirection to force said arms together, until the best sound-reproductionresults; and when the mechanism is not in use a turning back of the nutwill in each instance remove the strain from the resonators so that theymay be relaxed when idle and so will not become set from remaining in astrained state and lose their resonating quality. In my applicationSerial No. 88.835 I have disclosed a combination comprising an elasticvibrator (here afforded by 1--4-6-7), means to intermittently tensionthe same including electro-magnet and armature elements arrangedthereon, said vibrator being yieldable to vary the gap bctween saidelements, and adjustable means to cause such yielding of the vibratorand maintain the same in its thus-yielded state including a hollow shellhousing the vibrator. But in that case said elements were not adjustableindependently of the means to cause `yielding of the Vibrator.

In Figs. 4 and 5 I note that each resonator gradually varies inthickness from a substantially central point in all directions to itsmargin; in the present instance the construction is such that one of theextremes in thickness (i. c., its thinnest portion) is coincident bothwith its center and with the point of contact between it and what is ineti'ect a prolongation (14-15 or 17) of the member 1. In extensiveexperiments with resonators operated by a vibratory structure in contacttherewith I have found that it is indispensable, in order to reproducedifferent qualities of sound in the one reproducing apparatus withoutadjustment thereof (for example, the low-pitched tones of the cello andthe high-pitched tones possible with the violin) that the reproducershould have this form.

Having thus fully described my invention what I claim and desire tosecure by Letters Patent is:

1. In a sound reproducing apparatus, a system to be vibratcd includingan elastic flexible vibrating structure and means for exerting variableelastic fiexing pressure on said structure at either of two pointsthereof in substantially a common plane of flexure, in combination witheoactive electromagnet and armature elements arranged one on a part ofsaid system which is moved on iiexing of said structure and theothcr onanother part of said system.

2. In a sound reproducing apparatus` a system to be vibrated includingan elastic Hexible vibrating structure and means, wholly supported bysaid structure, for exerting variable elastic flexing pressure on saidstructure at either of two points thereof in substantially a commonplane Aot flexure, in combination with coactive electro-magnet andarmature elements arranged one on a part of said system which is movedon ilexparts of said system of which one moves relatively to the otheron flexing said structure.

' 4. In a sound reproducing apparatus, a system to be-vibrated includingan elongated elastic flexible vibratory structure, an elastic flexiblelever fulcrumed therein, and means connecting said lever and structureand arranged to flex the former transversely of its length, forexert-ing variable flexing pressure on said structure, in combinationwith coactive velectro-magnet and armature elements arrangedrespectivelyon parts of said system of whichone moves relatively to theother on flexing said structure.

In a sound reproducing apparatus, an elastic flexible vibratorystructure, an elastic flexible lever fulcrumed therein and means,connecting said lever and structure and arranged to flex the former, forexerting variable flexing pressure on said structure, 1n

combination with coactive electro-magnet and armature elements arrangedrespectively on a part of said lever and apart of said structure as towhich the former part is movable relatively to the latter on flexing ofsaid lever.

6. In a sound reproducing apparatus, an elastic flexible vibratostructure, an elastic flexible lever fulcrume therein and separatemeans, connecting said 'lever with said structure at two points thereofinsubstantially a common plane of flexure, for exerting variable flexingpressure on said structure, in combination with coactive electro-magnetand armature elements arranged respectively on a part of said lever andapart of said structure asto which the former art is movable relativelyto the latter` on exing of said lever. A 'l 7. Ina sound reproducer, abent elastic member, an elastic lever bearing a ainst one extremity ofSaid. member and aving a pivotal support on the other, an electromagnetand its armature carried one by the first-named extremity and the otherby said lever and opposed to each other, and means, connected with thelever remote from its bearing and pivoting points, to flex the same fromone of said extremities toward the other and thereby adjust the spacingbetween the magnet and its armature.v

8. In combination, and elastic vibrator, means to intermittently tensionthe same in cluding electro-magnet and armature elements arranged andone being .adjustable thereon-toward and-from the other to-vary the gapbetween them, saidV vibrator being yieldable to also vary said gap, andadjustable means to cause such yielding of the vibrator and maintain thesame in its thus-- yielded state including -a hollow shell housing thevibrator.

9.111 combination, an elastic vibrator, means to intermittently tensionthe same including electro-magnet and armature elements arranged and onebeing adjustable thereon toward and from the other to vary thegapbetween them, said vibrator being yieldable to also vary said gap, andmeans to cause such yielding of the vibrator and maintain the same inits thus-yielded state 4 including a resonant hollow shell housing thevibrator and an adjustable connection between the vibrator and shell.l0. A sound reproducer including, in combination, a concavo-convexintegral resonator shell formed to gradually vary in thickness fromsubstantially the center thereofin substantially all directions to itsmargin, and a vibrator having contact with the shell at one of itsextremes of thickness, said shell being normally held by the vibrator ina state of flexing tension. j.

11. A sound reproducer including, in-combination, an integral-hollowresonatin casing formed with a portion thereof gra uall increasing inthickness in substantially a directions radiating from the samepoint anda vibrator contained in the casing and having contact with such` portionat substantially said point and holding the casing normally in a stateof tension. j

In testimony whereof I alix my signature.

